Generally, the Dutch side operates on 110 volts AC (60-cycle) and has outlets that accept flat-prong plugs—the same as in North America. The French side operates on 220 volts AC (60-cycle), with round-prong plugs; you need an adapter and sometimes a transformer for North American appliances. The French outlets have a safety mechanism—equal pressure must be applied to both prongs of the plug to connect to the socket.